The Problem:-

“TV can’t play because the hard disk you chose in Settings is full. Clear space on this drive, or choose another drive.”
You get the above error when you are trying to watch Live TV,though  the hard drive is NOT full.

Resolution:-

Several things You can try:-

1]If you have Norton Staff-just uninstall that.

2]change the default location for recorded TV.

3]Keep in mind that Live TV is written to hard disk before being replayed so if you allocate more space it will eventually help you.